Can old brewed coffee make you sick?

by Lou
(San Diego)


I have a friend who brews a pot of coffee once a week and drinks a cup a day (warmed in the microwave) until it's gone. Sometimes that same pot sits on his counter for more than a week. I notice that he is sick quite often -- is it possible that he is getting sick from doing this?


Plenty of people keep cold coffee in the fridge for a week or so, and then microwave a cup or two each day.

Not exactly the best way to enjoy the finer flavors of a gourmet coffee, but it works for some people.

That's the amazing thing about coffee...some people love it like they love a fine wine, while others are just happy for a hot brew with a nice caffeine kick.

That said, if he doesn't keep it in the fridge, I would be a little more concerned. I'm not a doctor or any kid of medical practitioner, but I'm guessing there are some unpleasant moulds that would be happy to take residence in coffee that is sitting around at room temperature.

I would encourage your friend either to keep the coffee in the fridge, or brew more often.

Comments for Can old brewed coffee make you sick?

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Dec 20, 2023
Old coffee
by: Anonymous

If I have coffee in a and go away for several days and return there is mold floating on the top. So would not reccomend drinking old coffee left out.

Mar 26, 2020
no clue but I don't feel too good
by: Anonymous

I just had some (black) espresso I kept in the fridge overnight from yesterday morning. I feel super icky after drinking it. It was rancid, and I have weird jitters and muscle aches... not sure why it made me feel like this but I guess it aint worth the risk

Feb 15, 2018
Re belly ache with ground coffee
by: Anonymous

I drank some organic ground coffee yesterday which was probably about 3-4 months old, I had the most horrible pains/cramps in my belly which moved up, down, side ways..all over the place, no sickness or diarrhea. It had gone by morning, I'm convinced it was the coffee.

Jun 11, 2017
sick from coffee?
by: Anonymous

Also just thought about how using cold brew without using heat---in my case,mold or bacteria may be present that wasn't killed by boiling. I got stomach cramps off and on, since the coffee I have used recently was cheap and not organic--so it also has LOTS of pesticides. Anyone know the symptoms for pesticides? They are on and in virtually everything now.
I don't want to blame the coffee until I research some more--

Jun 11, 2017
coffee making me sick
by: Anonymous

I just recently started cold brewing my coffee--no heat to it at all. I drink it as cold coffee. The next day I got a huge pain in my lower back to where I could hardly walk. Also stomach cramps. I know this has nothing to do with my spine--it was kidneys or something of the sort as I had a first attack a couple of mo. earlier and after trying all the natural things finally crawled out to the car and went to the emergency, after I was finally seen and was being prepped for test---bam, I was like new????? Figured I must have had a stone. Ok, so then, here we go again, also with slight stomach cramps, I wrote down all the stuff I ate and did the day before and I had the cold coffee---with milk and sugar. I am going to try heating it to almost a boil before I cool it this time. I notice that grounds I store for the garden start smelling sour in 3 or so days, so I guess it is possible to get sick from--also If I don't drink my hot coffee until its cold. I will let you all know what I find out.

Oct 25, 2015
rancid coffee
by: lula

Several years ago i was sick all the time. Upset stomach with flu typs symptoms. Doctors couldn't resolve this.
I noticed that there were some coffee grounds in the water resoviour of my coffee maker & attemped to clean them out... Impossible task! These grounds were stuck & rancid. I used coffee pot cleaner, no use. I finally put bleach in thinkjng this would clean it.. nope... only bleached the grounds white. Only choice was to get a new coffee maker.
I found a great coffee maker that had a clear plastic water container that was removable... problem sloved... I noticed the coffee tasted better & the aroma was way better too...Not only that but my stomach/flu symptome went away.
So to answer the question of can old coffee make you sick: I say, You bet it can.
It is very important to use a clean coffee maker. Washed daily.
Maybe some people are not bothered by the rancid oils left behind by old coffee or a less than clean coffee maker but some people are very sensitive to rancid oils. Why chance it.

Dec 17, 2013
Can old brewed coffee make you sick? Not necessarily.
by: Anonymous

For many years now I've brewed a pot of coffee and kept it on the counter to drink it, usually up to 3 days old. I've never had any problems with my health because of it. I don't think I'd go past 4 days unless it was refrigerated. It would spoil for sure if you put any creamer and/or sugar into it. And as far as reusing a coffee cup, I reuse my travel mug all week. I rinse it out when I'm done. But I also drink my coffee black. Spoiled milk has its own schedule. Leave a glass of milk out in the summer and try it again in the winter. I assure you the summer milk will curdle much much faster, in less than a day likely.

Jul 21, 2010
Can old brewed coffee make you sick? May be.
by: Kit

I am replying to this post, because I was looking for complaints about old coffee making people sick.

I have noticed twice this year that when I do not wash my coffee cup for more than 3 days then the next day if I use the same unwashed cup, I experience an allergic reaction (sneezing, sore throat) and I get fever with in a day which lasts for 2-3 days.

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